1. Field of the Invention
The present invention relates to telecommunications networks and more particularly to telecommunications networks of the kind requiring communications between the network and terminals attached thereto without provision of a voice communications path at the initial phase of a communications call.
2. Related Art
Many services provided by telecommunications networks will require information additional to a telephone number for example to enable completion of a connection through the transport network. For example, credit or charge card calls may require entry of a personal identification number (PIN) and/or an account number prior to proceeding. Where such services are provided after the customer has been connected through the network to a peripheral a voice or other prompt may be used to request the customer to enter further detail. Such services are therefore often referred to as xe2x80x9cprompt and collectxe2x80x9d services.
Where a customer has a telephone instrument or other terminal adapted to signal the network by use of multi-frequency tones, it is possible for the prompt and collect service to operate by the coding of the tones without establishing a complete speech path through the network. However, many communications connections are not by way of analogue lines to the customer""s premises but are rather of a digital type and, more particularly, of a type known as ISDN in which a single customer connection carries a plurality 64 Kbs digital bearer channels and a data channel.
ISDN terminals do not function efficiently in the provision of multi-frequency tones until the terminal is put into. a speech phase. However, putting the call into the speech phase prior to effecting a connection simply to enable prompt and collect services to operate may result in charging difficulties as the customer equipment may see a network response as a valid answer.
Further, if the ISDN call originates from a data terminal, ISDN standards do not permit switching back to a data phase after switching into voice phase communication. In many cases also data terminals may not include multifrequency transmission capability and/or may not include speaker or headset facilities to receive voice prompts.
According to the present invention there is provided a telecommunications network including switch means which have customer connections which receive a bit stream from customers, the bit stream comprising the plurality of bearer channels and at least one data channel, control means of the switch being responsive to data from the data channel to set up bearer channel calls through the network, and network control means responsive to stored data associated with a calling connection identity or a called connection identity to accept data from another data network in respect of bearer channel calls.
Preferably the switch includes means responsive to a portion of the data transmitted in the data channel to forward received data either to control means of the switch or to a data network.
The data network may be of the kind referred to as an X25 network which may be the network from which the network control means recovers data.
The service control means may be arranged to cause means connected to the data network to transmit prompt information by way of the data network to the calling connection to prompt a user to forward further information by way of the data network.
In an alternative arrangement the data network may be an electronic mail type environment in which messages are transferred to an E-mail address of the network, apparatus associated with the service control function having an appropriate address to which mail relating to the bearer channel may be transmitted. The resource function associated with forwarding prompt data may forward prompt data to an E-mail address requiring a reply from the user.
According to a feature of the invention there is provided a digital telecommunications network having a plurality of switching units for providing transmission of digital bearer channels between first and second selectable service points, the second service point being determined by data from a data channel transmitted from the first service point, control means of the network being responsive to data identifying the first or second service points to provide additional functionality of the kind requiring further defining data from the first service point characterised in that an interface is provided between the control means of the network and a separate data network for providing transmission of data channels, the interface being responsive to the control means to transmit prompting data to the first service point by way of the data network and to collect data returned thereby for transmission to the control means such that completion of a call through the first network is modified by data received through the second network.